Buggy code:
public class Java extends Task { private CommandlineJava cmdl = new CommandlineJava ( ) ; private Environment env = new Environment ( ) ; private boolean fork = false ; private boolean newEnvironment = false ; private File dir = null ; private boolean failOnError = false ; private boolean append = false ; private Long timeout = null ; private Redirector redirector = new Redirector ( this ) ; private String resultProperty ; private boolean spawn = false ; private boolean incompatibleWithSpawn = false ; public void execute ( ) throws BuildException { File savedDir = dir ; int err = - 1 ; try { err = executeJava ( ) ; <START_BUG> if ( ( fork ) && ( Execute . isFailure ( err ) ) ) { <END_BUG> if ( failOnError ) { throw new BuildException ( ( "Java<seq2seq4repair_space>returned:<seq2seq4repair_space>" + err ) , getLocation ( ) ) ; } else { log ( ( "Java<seq2seq4repair_space>Result:<seq2seq4repair_space>" + err ) , MSG_ERR ) ; } } maybeSetResultPropertyValue ( err ) ; } finally { dir = savedDir ; } } public int executeJava ( ) throws BuildException { } public void setSpawn ( boolean spawn ) { } public void setClasspath ( Path s ) { } public Path createClasspath ( ) { } public Path createBootclasspath ( ) { } public void setClasspathRef ( Reference r ) { } public void setJar ( File jarfile ) throws BuildException { } public void setClassname ( String s ) throws BuildException { } public void setArgs ( String s ) { } public Argument createArg ( ) { } public void setResultProperty ( String resultProperty ) { } protected void maybeSetResultPropertyValue ( int result ) { } public void setFork ( boolean s ) { } public void setJvmargs ( String s ) { } public Argument createJvmarg ( ) { } public void setJvm ( String s ) { } public void addSysproperty ( Environment . Variable sysp ) { } public void addSyspropertyset ( PropertySet sysp ) { } public void setFailonerror ( boolean fail ) { } public void setDir ( File d ) { } public void setOutput ( File out ) { } public void setInput ( File input ) { } public void setInputString ( String inputString ) { } public void setLogError ( boolean logError ) { } public void setError ( File error ) { } public void setOutputproperty ( String outputProp ) { } public void setErrorProperty ( String errorProperty ) { } public void setMaxmemory ( String max ) { } public void setJVMVersion ( String value ) { } public void addEnv ( Environment . Variable var ) { } public void setNewenvironment ( boolean newenv ) { } public void setAppend ( boolean append ) { } public void setTimeout ( Long value ) { } public void setAssertions ( Assertions asserts ) { } protected void handleOutput ( String output ) { } public int handleInput ( byte [ ] buffer , int offset , int length ) throws IOException { } protected void handleFlush ( String output ) { } protected void handleErrorOutput ( String output ) { } protected void handleErrorFlush ( String output ) { } private void run ( CommandlineJava command ) throws BuildException { } private int run ( String [ ] command ) throws BuildException { } private void spawn ( String [ ] command ) throws BuildException { } protected void run ( String classname , Vector args ) throws BuildException { } public void clearArgs ( ) { } protected ExecuteWatchdog createWatchdog ( ) throws BuildException { } }

Fix:
if ( ( fork ) && ( err != 0 ) ) {